Vibration translator



Feb. 6, 1951 A, N. STANTON 2,540,796

VIBRATION TRANSLATOR Filed Nov. 28, 1949 2 Sheets-Sheet l Feb. 6, 1951A. N. STANTON 2,540,796

VIBRATION TRANSLATOR Filed Nov. 28, 1949 2 Sheets-Sheet 2 FIG. 4

o C0 Cd FIG. 3

INVENTCR. l

Patented Feb. 6, 1951 UNITED STATESA PATENT OFFICE VIBRATION TRANSLATORAustin N. Stanton, Garland, Tex. Application November 28, 1949, SerialNo. 129,782

This invention relates to energy translating devices and moreparticularly to energy translating devices which convert mechanicalvibrations into electrical energy.

This application is directed to the invention disclosed in my abandonedapplication Serial Number 565,161, led November 25, 1944.

In many applications, such as seismic exploration of the earths surfaceand analysis of structure vibration, it is desirable to translatemechanical vibrations into electrical energy having a characteristicwhich reflects the amplitude, shape and time relationship of themechanical vibrations., Extreme sensitivity and accuracy of translationare necessary and the translating device must therefore be unresponsiveto extraneous magnetic disturbances.

Accordingly, it is an object of my invention to provide a new andimproved means for translating mechanical energy into electrical energy.

It is another object of my invention to provide a new and improved meansfor translating mechanical vibrations into electrical energy having acharacteristic which reflects the amplitude, shape and time relationshipof the mechanical vibrations.

It is another object of my invention to provide a. new and improvedmeans for translating mechanical vibrations into electrical energy whichis unresponsive to extraneous magnetic disturbances.

It is still another object or my invention to provide a new and improvedmeans for translating mechanical vibrations into electrical energy, thevoltage of which is generated as a result of changes in the amount ofmagnetic flux owing in alternative magnetic circuits, the sum of thefluxes ilowing in the alternative circuits remaining substantiallyconstant.

Briefly stated, in the illustrated embodiment of my invention I providea new and improved vibration translator which comprises a tubular magnetand an armature mounted for movement along the central axis of thetubular magnet. The `armature comprises a helically wound coil 10Claims. (Cl. 171-209) 20 drawing, and its scope will be concentric withrespect to the central axis of the Vmagnet mounted between a central eldpiece and a tubular eld piece. The two eld pieces constitute alternativemagnetic flux paths and the amount of flux passing through each fieldpiece changes in accordance with the movement of the armature along thecentral axis of, and relative to, the tubular magnet although the sum ofthe magnetic uxes iiowing through the iield pieces remains substantiallyconstant regardless 2 of the movement of the armature. The change in theamount of flux passing through eachiield piece changes the magnetic ieldabout the coil and induces a potential in the coil. Any suitable meansmay be employed to transmit the mechanical vibrations to the armature toproduce cor,- responding movement of the armature with respect to thetubular magnet. The electric current induced by this relative movementwill have a potential which will reilectn the amplitude, shape and timerelationship of the mechanical vibrations. The electric currentsgenerated in the coil may be used or recorded by any conventional means,such as a reiiecting galvanometer controlling light projected onto a'moving photographic lm.

For a better understanding of my invention,

reference may be had to the following description taken in connectionwith the accompanying pointed out in the appended claims.

Figure 1 is a central longitudinal section showing a preferredembodiment of my invention with the armature in its normal medialposition;

Figure 2 is a central longitudinal section of the device shown in Figurel with the armature displaced in one direction from its normal, medialposition;

Figure 3 is a central longitudinal section ofthe device with thearmature displaced in the opposite direction from its normal, medialposition from the displacement direction shown in Figure 2 and Figure 4is a central longitudinal section of a modied form of my invention.

Referring to Figures l to 3 of the drawing, a tubular permanent magnetIE), magnetized parallel to its central axis, is provided at one endwith an annular pole piece Il which is concentric with respect to thecentral axis of the mag.- net I0 and which extends inwardly from .themagnet I0. The other end of magnet IB is provided with annular polepieces I2 and I3 which are separated by a cylindrical spacing block I4.-Pole pieces I2 and I3 are. also concentric with respect to the centralaxis and extend inwardly;

Magnet I i3 ,is preferably made of alloy steel l'1av.I ing a highmagnetic strength while pole-'pieces II, I2, I3 and block I4 arepreferably made of soft steel having alow reluctance.

Mounted on pole pieces II and I3 are annular spacing members I5 and I,respectively. Members I5 and I5 are of nonmagnetic material, such asbrass, and are concentric with respect to theA central axis oi magnetvl.Members I 5 and I6 act as anchoring means for resilient means il and i8,respectively, which are preferably diaphragm springs and which supportan armature I9 by means of members 20 and 2 i. Armature I9 comprises acentral field piece 22 having a central core 23 provided at its endswith disks 2li and 25. Central iield piece 22 is concentric with respectto the central axis of the magnet lil and, because of its resilientmounting, is movable along the central axis. A .pair of washers .2s and2.3 of nonmagnetic material are mounted upon core 23 and about disks 2liand 25. A helically wound coil 28 is disposed about core 23 betweenwashers 2B and 21. The central axis of coil L3 coincides with thecentral axis of magnet ll. The two ends (not shown) of the coil 28 maybe brought to stationary terminals (not shown) through flexible leads.The ends may also be .connected to the resilient means il and It whichwould have to be insulated from the other elements of the device. Bothmethods of bringing ou-t the two ends of the coil are conventional inthe art. lCurrents generated in coil 23 and brought out in anyconventional manner may be used or recorded by any well known means,such as a reflecting galvanometer controlling light projected on amoving strip of iilm.

A tubular field piece 29 having at its ends outwardly extending anges 3@and 3| is mounted on central field piece 22 between washers 25 and 21.The peripheral edges of ilanges 35i and 3i, washers 2li and 21, anddisks 2li and 25 lie in the same cylindrical plane. Coil 22 lies betweencore 23 and tubular field piece 22. `Field pieces 22 and 29 are of softsteel having a low reluctance.

In its normal, medial position, as is shown in Figure l, armature I9presents two paths of equal reluctance to the magnetic flux of magnetI0. The reluctance of the magnetic flux path comprising annular polepiece i2, spacing block I2, pole piece I3, disk 25, core 23, disk 2liand pole piece II is equal to the reluctance of the magnetic ilux pathcomprising annular pole piece i2, tubular iield piece 22 and annularpole piece li. The two `paths have the same reluctance only whenarmature IS is in its medial position, and, when it is in this position,equal amounts of magnetic iiux now through each of the flux paths.

When armature i9 is 'displaced to the position shown in Figure 2, disks`"124i and 25 are ,moved away from annular pole pieces l l and i3thereby including relatively large air gaps in the magnetic ux pathwhich comprises core 23. The reluctance of this magnetic iux path,therefore, is increased. Tubular Vfield piece is moved at the same timeAinto a position where its flanges 30 and 3| are in close relation withannular pole pieces II and I2. The reluctance of the magnetic flux pathwhich comprises tubular eld piece 29` is therefore decreased. Due tothese changes in the reluctances of the two paths, the amount ofmagnetic flux flowing in the path which comprises tubular iield piece 29is increased While the amount of flux flowing in the path which;comprises central ileld piece I9 is decreased. .The changing of theamount of flux flowing through each path changes the magnetic eld aboutcoil 28 thereby inducing a potential in coil 28. As will be wellunderstood by those skilled in the art, the potential induced in coil'26 will vary with the amount and speed of displacement of armature I9with respect to magnet l0.

When armature is is displaced to the position shown in Figure 3, thereluctance of the flux path which includes tubular field piece 29 isincreased since relatively large air gaps are included in the pathbetween pole piece II and flange 3U, and between pole piece I2 andilange 3i. At the same time the reluctance of the flux path whichincludes central field piece 22 is decreased since disks 2li and 25 arebrought into close relation with pole pieces il and I3, respectively.The resultant changes in the amount of flux nowing in the two flux pathsproduce a change in the magnetic field about coil 28 but the change isopposite to the change produced when armature I9 is moved to theposition of Fig-ure 2. in moving from its medial position to theposition shown in Figure 2, armature I9 causes a large portion of themagnetic lines of force of magnet i@ to move farther away from thecentral axis of magnet l. The magnetic lines of force cut the coil 28 intheir movement and induce a potential in coil 28. When armature i@ movesto the position shown in Figure 3, it causes the magnetic lines of forceof magnet itv to move closer to the central axis of vmagnet iii. Intheir movement, the magnetic lines of force again cut the coil 28 butthis time ltheir direction of movement is directly opposite to thatcaused by the movement lof armature I9 to the position of Figure 2. Apotential of opposite polarity to that induced by the movement ofarmature i9 to the position of Figure 2 is therefore induced in coil 23.As will be well `understood by those skilled in the art, the potentialsinduced in coil 28 will vary in accordance with the speed and amount ofaxial displacement of armature E9 with respect to vmagnet Ill. Anysuitable means may be employed to transmit the mechanical vibrations toarmature I9 and produce corresponding axial movement of armature Illalong the central axis of magnet Il).

It is to be noted that coil 28, during normal displacements of armatureI9, moves parallel to the magnetic Vline of force of magnet I0.Substantially no lines of force are cut by, and substantially nopotential is induced in, coil 28 due to this movement of coil 23. It isonly the shifting of the magnetic ux from one .path to the other whichcauses movement of the magnetic lines of force in a direction whichresults in coil 28 cutting the magnetic lines of force and induces apotential in coil 2S.

The potentials induced in coil 28 will correspond very closely inamplitude, shape and time relation to the mechanical vibrationstransmitted to armature i9 since under normal oper.- ating conditionsthe losses due to reluctance will remain substantially constant whateverthe position of armature i9 with respect to the magnet Iii. The magneticattraction of pole pieces il, i2 and I3 for elol Ipieces 22 and 29 willalso remain substantially constant under normal operating conditions.Extraneous magnetic disturbances do not aiiect the potentials induced incoil 28 since the soft iron field pieces 22 and 25 enclose coil 2,3 andShield it from such `magnetic disturbances. 'Magnet Iii, pole pieces II,l2 and i3, and rspacing'block I4 also act as shield*- ing lmeans againstextraneous magnetic disturbances. Further shielding means may beprovided in the form of soft iron caps (not shown) over each end of myvibration translator.-

Figure 4 illustrates a modied form of the device disclosed in Figures 1to 3 in which a movable rod-shaped magnet 32 is utilized instead of thetubular magnet i0. p

The rod-shaped magnet 32 is provided at one end with a disk-shaped polepiece 33 and at the other end with disk-shaped pole pieces 34 and 35which are separated by a circular spacing block 36.

Magnet 32 and its pole pieces 33, 34 and 35 are resiliently mounted bymeans of diaphragm springs 37 and 38 and blocks 39, 40, 4| and 42 upon acylindrical iield piece 43 which has at its ends inwardly extendingannular members 44 and 45. A tubular iield piece 46 provided at its endswith inwardly projecting flanges 41 and 48 is mounted on cylindricaliield piece 43. Annular members 49 and 50, which are of a suitablenonmagnetic material, separate iield piece 43 from field piece 46. Atubular coil is disposed between the iield pieces and is provided withsuitable leads (not shown) which conduct the current generated in thecoil to any suitable instrument. The mode of operation of the deviceillustrated in Figure 4 is substantially the same as that of the deviceillustrated in Figures 1 to 3. The device comprises two flux paths oneof which comprises pole piece 34, field piece 45 and pole piece 33. Theother flux path comprises pole piece 34, spacing block 36, pole piece35, field piece 43, and pole piece 33. The combined reluctance of thetwo ux paths remains substantially constant during normal displacementsof magnet 32 The individual reluctances of the two ux paths, however,vary in accordance with the displacement of magnet `32 in the samemanner as the reluctances of the two iiux paths of the deviceillustrated in Figures 1 to 3.

In order to minimize eddy currents generated inthe various components ofthe magnetic flux paths by the movement of the magnetic lines of force,the various components of my vibration translator may be laminated inplanes parallel to the magnetic lines of force in the manner well knownto those skilled in the art. The eddy currents may be employed howeverto provide a magnetic damping means for the moving parts of the device.

While I have shown and described preferred embodiments of my invention,it will be obvious to those skilled in the art that changes andmodifications may be made without departing from my invention, and I,therefore, aim in the appended claims to cover all such changes andmodifications as fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. In a device for translating mechanical energy into electrical energy:a tubular magnet having a central axis, said magnet being magnetizedparallel to said central axis; a iirst annular pole piece concentricwith respect to said central axis extending inwardly from one end ofsaid magnet; a second and a third annular pole pieces separated by anannular spacing block concentric with respect to said central axisextending inwardly from the other end of said magnet; an armatureresiliently mounted for movement along said central axis and having acentral axis coincident with said central axis of said magnet, saidarmature comprising a central field piece having a central core providedat each end with a disk, a tubular iield piece concentric with respectto said central axis mounted on said central F field piece between saiddisk and separated from said disks by ncnmagnetin annular washers` saidtubular eld piece having at its ends outwardly extending annular iiangesabutting said washers, the peripheral edges of said disks, washers andanges lying in the same cylindrical'plane, one of said Washers lying inthe same plane normal to said central axis as said rst annular polepiece when said armature is in its normal position, the other of saidwashers and its abutting ange and disk lying in planes parallel to andbetween the planes of said second and third annular pole pieces whensaid armature is in its normal position, and a tubular coil between saidcore and Said tubular iield piece having a central axis coincident withsaid central axis of said tubular magnet.

2. In a device for translating mechanical energy into electrical energy:a tubular magnet having a central axis, said magnet being magnetizedparallel to said central axis; a rst annular pole piece concentric withrespect to said central axis, extending inwardly from one end of saidmagnet; second and third annular pole pieces separated by an annularspacing block concentric with respect to said central axis extendinginwardly from the other end of said magnet; and an armature resilientlymounted for movement along said central axis and having a central axiscoincident with said central axis of said tubular magnet, said armaturecomprising a central field piece having a central core provided at eachend with a disk, a tubular field piece mounted between said disks andseparated from said disks, said second annular pole piece and saidtubular pole piece comprising a portion of a first magnetic flux path,said third annular pole piece and said central eld piece constituting aportion of a second magnetic flux path, the reluctance of one magneticflux path decreasing as the reluctance of the other path increases uponmovement of said armature along said central axis, and a tubular coilbetween said core and Said tubular eld piece having a central axiscoincident with central axis of said tubular magnet.

3. In a device i'or translating mechanical energy into electricalenergy:r a tubular magnet having a central axis, said magnet beingmagnetized parallel to said central axis; a pair of pole pieces spacedfrom one another along said central axis at one end of said magnet; anarmature resiliently mounted for movement aiong said central axis, saidarmature comprising a tubular coil having a central axis coincident withsaid central axis of said magnet; a iirst magnetic means providing aportion of a iirst path within said tubular coil for the flux of saidmagnet; and a second magnetic means about the outside cylindricalsurface of said coil providing a portion of a second path for the iiuxof said magnet, said pair of pole pieces and said nrst and second iieldpieces cooperating to maintain the reluctance or" said first and secondflux paths substantially constant, the reluctance of one path decreasingand the reluctance of the other path increasing upon movement of saidarmature along said central axis of said magnet, one of said magneticmeans approaching one or said pole pieces and the other of said magneticmeans simultaneously withdrawing from the other of said pole pieces uponmovement of said armature along said central axis of said magnet.

4. In a device for translating mechanical energy into electrical energy:a unit comprising a tubular coil having a central axis, a iirst meanswithin said coil providing a portion of a rst ma gnetic flux path, and asecond means about said coil providing a portion of a second magneticiiux path; a magnet symmetrically arranged about .said central axis andmagnetized parallel to said central axis; and a pair of pole piecesspaced from one another along lsaid central axis and xed to one end ofsaid magnet; a single pole piece on the other end of said magnet, saidmagnet and said unit being resiliently connected for relative movementalong said central axis, one of said pole pieces providing a portion ofsaid first magnetic flux path and the other of said pole piecesproviding a portion of said second magnetic flux path, said iirst andsecond ux paths having a substantially constant combined reluctance, thereluctance of one path decreasing and the reluctance of the other pathsimultaneously increasing upon relative movement between said magnet andsaid unit along said central axis, one of said pair of pole pieces andone of said means approaching each other and the other of said pair ofpole pieces and the other of said means simultaneously withdrawing fromone another upon relative movement between said unit and said magnetalong said central axis, said one ci said means simultaneouslyappro-aching said single pole piece and said other of said meanssimultaneously drawing away from said single pole piece.

5. In a device for translating mechanical energy into electrical energy:a unit comprising a tubular coil having a central axis, a first meanswithin said coil providing a portion of a first magnetic iiux path, asecond means about the outer surfaces of said coil providing a portionof a second magnetic flux path, and first and second annular means ofnon-magnetic material separating said iirst and second means; a magnetsymmetrically arranged about said central axis and magnetized parallelto said central axis; a rst pole piece on one end of said magnet lyingin a plane normal to said central axis and coincident with the plane ofsaid Afirst annular means when said unit is in no-rmal position withrespect to said magnet; second and third pole pieces separated by aspacing block on the other end of said magnet and lying in planes normalto said central axis; second and third pole pieces separated by aspacing block on the other end of said magnet and lying in planes normalto said central axis, said second annular means lying in a plane normalto said central axis and rnedially between the planes of said second andthird pole pieces when said magnet and unit are in normal position withrespect to each other, said rst and. second magnetic paths having asubstantially constant combined reluctance, the reluctance of one ofsaid paths decreasing and the reluctance of the other of said pathssimultaneously increasing upon relative movement between said magnet andsaid unit along said central axis; and resilient means connecting saidunit and said magnet to allow relative movement between said magnet andsaid unit along said central axis.

6. In combination: a cylindrical eld piece having at each end aninwardly extending annular member; a tubular iield piece having at eachend an inwardly extending flange mounted within said cylindrical fieldpiece; annular means of non-magnetic material between each of saidflanges and its adjacent annular member; a tubular coil between said eldpieces; said eld pieces and said coil being concentric with respect to acentral axis; said flanges, annular means and annular members havinginner surfaces lying in a common cylindrical plane concentric withrespect to said central axis; a magnet resiliently mounted within saidtubular iield piece for move- `ment along said central axis, said magnetbeing magnetized parallel to said central axis; a circular iield pieceon one end oi said magnet lying adjacent to one of said annular meanswhen said magnet is in its normal position with lrespect to said eldpieces; second and third pole pieces separated by a spacing block on theother end of said magnet, the other of said annular means and itsadjacent flange and inwardly extending annular member lying in planesparallel to and between the planes of said second and third pole pieceswhen said magnet is in its normal position, said magnet and said polepieces being concentric with respect to said central axis.

'7. In a device for translating mechanical energy into electricalenergy: a magnet having a central axis, said magnet being magnetizedparallel to said axis; a pair of pole pieces fixed to one end oi saidmagnet, said pole pieces being spaced along said axis and lying inplanes perpendicular to said axis; a single pole piece on the other endof said magnet; a coil concentric with respect to said axis; meansresiliently connecting said magnet and said coil for reciprocal movementof said coil and said magnet relative to each other along said centralaxis and parallel to the lines of force of said magnet; a iield piecewithin said coil; and a eld piece around said coil, said field piecescooperating with said pair of pole pieces to cause movement of saidmagnetic lines of force during said relative movement between saidmagnet and said coil to induce a potential within said coil, one of saideld pieces and one of said po-le pieces approaching one another and theother of said iield pieces and the other of said pole piecessimultaneously drawing away from each other upon relative movementbetween said magnet and said coil along said central axis, said one ofsaid eld pieces simultaneously approaching said single pole piece andsaid other of said field pieces simultaneously drawing away from saidsingle pole piece.

8. In a device for translating mechanical energy into electrical energy:a magnet having a central axis, said magnet being magnetized parallel tosaid axis; a pair of pole pieces spaced along said central axis andiixed to one end of said magnet; a single pole piece on the other end ofsaid magnet; a coil concentric with respect to said axis; meansresiliently connecting said magnet and said coil for reciprocal movementof said coil and said magnet relative to each other along said centralaxis and parallel to thel lines of force of said magnet; a field piecewithin said coil; and a field piece around said coil, said field piecesbeing concentric with respect to Asaid central axis and providing incooperation with said pole pieces alternative ilux paths for themagnetic ilux of said magnet whereby relative movement .between saidmagnet and said coil along said axis causes shifting of the magneticflux of said magnet from one path to the other and results in themovement oi said magnetic lines of force relative to said coil inducinga potential in said coil, one of said pole pieces approaching oneanother and the other of said iield pieces and the other of said polepieces sim-u1- taneously drawing away from one another upon relativemovement of said magnet and said coil along said central axis, said oneof said eld pieces Simultaneously approaching said single pole piece andsaid other of said eld pieces simultaneously drawing away from saidsingle pole piece.

9. In combination: a unit comprising a coil having a central axis, a eldpiece within said coil providing a portion of a rst magnetic flux path,and a tubular eld piece about said coil having a central axis coincidentwith said first mentioned central axis providing a portion of a secondmagnetic flux path; a tubular magnet symmetrically arranged about saidcentral axis and magnetized parallel to said central axis; and a pair ofannular pole pieces fixed to one end of 'said magnet and spaced from oneanother along said central axis, said unit being mounted within saidmagnet for movement relative to said magnet along said central axis, oneof said pole pieces providing a portion of a second magnetic flux path,said iirst and second ux paths having a substantially constant combinedreluctance, the reluctance of one path decreasing and the re luctance ofthe other path simultaneously increasing upon relative movement betweensaid magnet and said unit along said central axis, one of said ileldpieces and one of said pole pieces approaching one another and the otherof said field pieces and the other of said pole pieces simultaneouslydrawing away from one another upon relative movement between said unitand said magnet along said central axis.

10. In combination: a unit comprising a coil having a central axis, arst tubular field piece within said coil providing a portion of a firstmagnetic Ilux path, and a second tubular field piece about said coilproviding a portion of a second magnetic flux path, said coil and saidiield pieces having coincident central axes; a magnet within said firsttubular field piece having a central axis coincident with said centralaxes and magnetized parallel to said central axis; and a pair of polepieces iixed to one end of said magnet and spaced from one another alongsaid central axis, one of said pole pieces providing a portion of saidfirst magnetic ux path and the other of said pole pieces providing aportion of a second magnetic ux path, said rst and second flux pathshaving a substantially constant combined reluctance, the reluctance ofone path decreasing and the reluctance of the other path simultaneouslyincreasing upon relative movement between said magnet and said unitalong said central axis, one of said field pieces and one of said polepieces approaching one another and the other of said field pieces andthe other of said pole pieces simultaneously drawing away from oneanother upon relative movement between said unit and said magnet alongsaid central axis.

AUSTIN N. STANTON.

REFERENCES CITED The following references are of record in the le ofthis patent:

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